OAKLAND  Thursdays news on Sean Manaea and Brett Anderson was not particularly encouraging for either As starting left-hander.

Manaea is out with rotator cuff tendonitis and As manager Bob Melvin on Thursday labeled his chances of returning this season at less than 50 percent. Anderson, meanwhile, has been diagnosed with irritation of the ulnar nerve in his forearm, and was scheduled to meet with doctors later Thursday, according to Melvin, to determine the next course of action. Anderson was initially diagnosed with a strained left forearm.

Manaea had made every start this season, going 12-9 with a 3.59 ERA in 27 games, including a no-hitter against Boston on April 21. Anderson is 3-4 this year with Oakland with a 4.02 ERA.

With Anderson and Manaea out indefinitely, the As are turning to Frankie Montas for Thursdays series opener against the Seattle Mariners, and for Daniel Mengden to take a spot in the rotation for the time being.

The As have had 13 pitchers start games this season.

Melvin was asked if he feels snake bit by the amount of pitchers hes seen go on the disabled list.

Its happened kind of in waves since spring training, so, at this point, not really, Melvin said. You expect some injuries, maybe not as many as weve had.

Obviously the Manaea situation, with a guy thats been basically our ace the entire season, stings a little bit more. Not that any of these dont hurt. But if you sit around and feel sorry for yourself and think youre snake bit, then its a distraction you dont need.

We do have some guys that have been productive for us this year in Montas and Mengden. Its their time to step up.

Manaea said he felt sore Aug. 25, a day after he threw five innings against Minnesota, when he was playing catch. He played catch again the following day, and the soreness lingered  which he added is unusual for him.

Ive been sore there before, but this is, I guess, a little more intense, he said. Its not like it got any better. Usually after day two, it calms down a bit.

Manaea, who is on a dose pack right now, hasnt ruled out a return next month.

Its super frustrating, Manaea said. I feel like Im letting everyone down. It really, really sucks that it has to happen right now. But theres nothing I can do about it except try to get healthy and hopefully help this team by the end of the season.

Melvin said Andrew Triggs, on the disabled list with right arm nerve irritation since May 18, will start a rehab assignment in the near future. Melvin said there was nothing imminent for Paul Blackburn (right elbow lateral epicondylitis). Blackburn, who has missed 46 games, said Thursday afternoon that hell throw a 30-pitch bullpen session Friday, throwing fastballs and changeups.

Montas and reliever J.B. Wendelken were officially brought up from Triple-A Nashville on Thursday, as the As sent back down reliever Ryan Dull and outfielder Nick Martini.

In 15 games after he was recalled July 7, Martini hit .394. He struggled at the plate lately, though, going 12-for-58 (.207) over his previous 19 games. Dull, who was recalled from the Sounds on Tuesday, threw two shutout innings for the As in their 5-4 loss to Houston on Wednesday. Martini and Dull should both be back after rosters expand in September, Melvin said.

It certainly is not ideal to have a two-man bench, for Thursdays game and possibly beyond, Melvin said. And we knew in some point in time during this stretch, 20 days against the teams that were been playing against, that our bullpen would be taxed enough that wed have to do something a little bit differently.

OAKLAND  Thursdays news on Sean Manaea and Brett Anderson was not particularly encouraging for either As starting left-hander.

Manaea is out with rotator cuff tendonitis and As manager Bob Melvin on Thursday labeled his chances of returning this season at less than 50 percent. Anderson, meanwhile, has been diagnosed with irritation of the ulnar nerve in his forearm, and was scheduled to meet with doctors later Thursday, according to Melvin, to determine the next course of action. Anderson was initially diagnosed with a strained left forearm.

Manaea had made every start this season, going 12-9 with a 3.59 ERA in 27 games, including a no-hitter against Boston on April 21. Anderson is 3-4 this year with Oakland with a 4.02 ERA.

With Anderson and Manaea out indefinitely, the As are turning to Frankie Montas for Thursdays series opener against the Seattle Mariners, and for Daniel Mengden to take a spot in the rotation for the time being.

The As have had 13 pitchers start games this season.

Melvin was asked if he feels snake bit by the amount of pitchers hes seen go on the disabled list.

Its happened kind of in waves since spring training, so, at this point, not really, Melvin said. You expect some injuries, maybe not as many as weve had.

Obviously the Manaea situation, with a guy thats been basically our ace the entire season, stings a little bit more. Not that any of these dont hurt. But if you sit around and feel sorry for yourself and think youre snake bit, then its a distraction you dont need.

We do have some guys that have been productive for us this year in Montas and Mengden. Its their time to step up.

Manaea said he felt sore Aug. 25, a day after he threw five innings against Minnesota, when he was playing catch. He played catch again the following day, and the soreness lingered  which he added is unusual for him.

Ive been sore there before, but this is, I guess, a little more intense, he said. Its not like it got any better. Usually after day two, it calms down a bit.

Manaea, who is on a dose pack right now, hasnt ruled out a return next month.

Its super frustrating, Manaea said. I feel like Im letting everyone down. It really, really sucks that it has to happen right now. But theres nothing I can do about it except try to get healthy and hopefully help this team by the end of the season.

Melvin said Andrew Triggs, on the disabled list with right arm nerve irritation since May 18, will start a rehab assignment in the near future. Melvin said there was nothing imminent for Paul Blackburn (right elbow lateral epicondylitis). Blackburn, who has missed 46 games, said Thursday afternoon that hell throw a 30-pitch bullpen session Friday, throwing fastballs and changeups.

Montas and reliever J.B. Wendelken were officially brought up from Triple-A Nashville on Thursday, as the As sent back down reliever Ryan Dull and outfielder Nick Martini.

In 15 games after he was recalled July 7, Martini hit .394. He struggled at the plate lately, though, going 12-for-58 (.207) over his previous 19 games. Dull, who was recalled from the Sounds on Tuesday, threw two shutout innings for the As in their 5-4 loss to Houston on Wednesday. Martini and Dull should both be back after rosters expand in September, Melvin said.

It certainly is not ideal to have a two-man bench, for Thursdays game and possibly beyond, Melvin said. And we knew in some point in time during this stretch, 20 days against the teams that were been playing against, that our bullpen would be taxed enough that wed have to do something a little bit differently.